The aim of this research program is to investigate the anti-hemostatic and anti-inflammatory compounds in vector saliva that allows efficient blood feeding and enhancement of pathogen transmission. Novel pharmaceuticals and novel targets for vaccine development will be ultimate benefits of this program. 1) Novel anticoagulants discovery: An anti-X and an anti-V anticoagulant peptide were characterized from the bed bug Cimex lectularius and from the black fly Simmulium vittatum, respectively. 2) Characterization of salivary anti-platelet activities: Apyrase activities from the bed bug Cimex lectularius was characterized and cloned, and the apyrase activities of over 20 different species of triatomine bugs was identified and characterized. The salivary apyrase of the mosquito Anopheles albimanus was purified and microsequence obtained. 3) Discovery of novel vasodilators: The vasodilator from the black fly Simmulium vitatum was expressed by a baculovirus expression system and the mode of vasodilation characterized. The salivary vasodilator of the fly Culicoides variipennis was characterized. The salivary peroxidase vasodilator of the mosquito anopheles albimanus was shown to possess a diaphorase activity. 4) Salivary anti-inflammatory agents: Protocols for purification of the salivary kininase and anti-complement activities of the Lyme disease vector, Ixodes scapularis, were determined.